On Tue, Aug 25, 2020 at 11:23:56AM +0200, Kurt Kanzenbach wrote: > On Mon Aug 24 2020, Vinicius Costa Gomes wrote: > > Hi, > > > > Kurt Kanzenbach <kurt@xxxxxxxxxxxxx> writes: > > > [snip] > >> + /* Setup timer for schedule switch: The IP core only allows to set a > >> + * cycle start timer 8 seconds in the future. This is why we setup the > >> + * hritmer to base_time - 5 seconds. Then, we have enough time to > >> + * activate IP core's EST timer. > >> + */ > >> + start = ktime_sub_ns(schedule->base_time, (u64)5 * NSEC_PER_SEC); > >> + hrtimer_start_range_ns(&hellcreek_port->cycle_start_timer, start, > >> + NSEC_PER_SEC, HRTIMER_MODE_ABS); > > > > If we are talking about seconds here, I don't think you need to use a > > hrtimer, you could use a workqueue/delayed_work. Should make things a > > bit simpler. > > I've used hrtimers for one reason: The hrtimer provides a way to fire at > an absolute base time based on CLOCK_TAI. All the other facilities such > as workqueues, timer list timers, etc do not. That still doesn't justify the complexity of irqsave spinlocks and such. You could just as well schedule a workqueue from that hrtimer and have process context... Thanks, -Vladimir
